This laboratory will prepare and purify deoxyoligonucleotides for the various investigators. The facility will have two functions: preparation of unmodified oligomers derived from the four natural deoxynucleosides and preparation of carcinogen-modified oligomers or halogen-substituted oligomers for use in substitution reactions. Small quantities of the unmodified oligomers will be needed for genetics experiments; the facility will also prepare the larger quantities needed for NMR experiments. While the preparation of normal oligomers might be contracted out to commercial laboratories, the irreplaceable function of the laboratory will be to prepare structurally modified oligomers using novel reagents developed in Project 1. In some case only minute amounts of adducted oligomers will be required, i.e., for molecular biological experiments, but much of the proposed work will require relatively large quantities. The NMR experiments require milligram quantities since useful NOESY spectra generally require at least 2-4 mM concentrations in a volume of 0.4 mL; similarly X-ray diffraction studies require relatively large quantities for preparation of crystals.